Category
Purpose
Makes the compiler sensitive to the case of letters in names.
Syntax
>>- -U---------------------------------------------------------><
@PROCESS:
@PROCESS MIXED | NOMIXEDDefaults
By default, the compiler interprets all names as if they were in lowercase. For example, Abc and ABC are both interpreted as abc and so refer to the same object.
Usage
You can use this option when writing mixed-language programs, because Fortran names are all lowercase by default, while names in C and other languages may be mixed-case.
If -U is specified, case is significant in names. For example, the names Abc and ABC refer to different objects.
This option changes the link names used
to resolve calls between compilation units. It also
affects the names of modules and 
submodules
and thus the names of their .mod and .smod files.
Restrictions
The names of intrinsics must be all in lowercase when -U is in effect. Otherwise, the compiler may accept the names without errors, but the compiler considers them to be the names of external procedures, rather than intrinsics.
The XL Fortran Version 2 requirement that keywords be all lowercase no longer applies.
Related information
This is the short form of -qmixed. See -qmixed.